King — Preliminary Notice of a Memoir on Rock-jointing. 329 



Lochaber have been examined by him, with the result of his having 

 become convinced that they are ancient sea-margins : 1495 feet is the 

 height usually stated of these terraces ; but he detected on the flanks 

 of Ben J^evis and the opposite mountains the like features, which 

 must reach to an altitude of between 2000 and 3000 feet. Besides 

 the raised shell-beaches standing at a comparatively low level on the 

 coasts of JSTorway, terraces have been lately observed and described by 

 Dawkins, which occur on the Dovrefelds, at the heights of from 2000 

 to 3100 feet. Darwin's account of the remarkable examples that 

 occur in Patagonia, up to the height of 1300 feet, leaves no doubt on 

 the present writer's mind that they have been formed by the action of 

 the sea. Hector has described vast terraces on both the Atlantic and 

 Pacific slopes of the Bocky Mountains, stretching from Athabasca 

 Biver to llexico, and rising one above another to heights ranging 

 from 3500 to 4500 feet above the level of the sea. The late Daniel 

 Sharpe made known the occuiTence of lines of erosion on the inner 

 and outer flanks of the Swiss Alps, at about 4800, 7500, and 9000 feet 

 above the sea. And, to finish what could be made a much longer 

 list,. Rudolph Grriesbach has described terraces in !N"atal lying at 

 heights of about 1000, 2300, and 5000 feet : it would also appear 

 that these correspond with certain of the plateaus common in the 

 Cape Colony. In short, it may be safely stated that marine terraces 

 are to be seen in every region of the globe. 



In the deep valleys of the lofty southern buttress — Great range of 

 Thibet — terraces ascend to the height of 16,000 feet ; but as these may 

 have been formed along the shores of elevated lakes, such as are now 

 in Ladak and adjacent countries, it would be unsafe to classify them 

 with the marine representatives that have been noticed. 



The writer, nevertheless, maintains that a number of geological 

 evidences afforded by the vast area last noticed, combined with the 

 proofs already brought forward, establish the conclusion that vertical 

 movements, equal to hemispheres in extent, have affected not only 

 High Asia, but the entirety of the earth's surface ; elevating conti- 

 nents, including their mountains and plateaus, at the same time 

 uplifting the bed of the intervening oceans, thousands of feet above 

 their present level ; or plunging them as deeply in the opposite 

 direction. 



Without denying that the level of the sea may have undergone 

 great fiuctuations at intervals during past geological time, and that 

 such changes may have participated, to an extent far beyond what 

 physicists and hydrographers are at present disposed to admit, in 

 effecting phenomena which, for convenience sake, he collectively 

 ascribes to vertical movements in the earth's crust, — or, without 

 offering any opinion respecting the hypotheses suggested by Babbage, 

 Herschel, and others, as to the cause of phenomena of elevation, — it 

 does not appear improbable to the author that vertical movements 

 have by slow degrees, and during a series of vast chronological terms, 

 alternately elevated and depressed opposite areas corresponding in 

 extent with a hemispherical division of the globe. 



